1. Technical Field
The present invention relates to a positioning device to position a member such as a sensor relative to an intermediate transfer belt, and an image forming apparatus including the positioning device.
2. Related Art
In image forming apparatuses such as a copier, a printer, a facsimile machine, or a multifunction apparatus including several of the capabilities of the above devices, as a method to properly control a density or a position of a toner image, an image pattern is formed on a surface of an intermediate transfer belt and is detected by a sensor serving as a pattern detector.
In order to improve precision in the detection by the sensor, the sensor needs to be positioned close to the surface of the intermediate transfer belt as a detection target. However, when the sensor is positioned close to the surface of the intermediate transfer belt, the surface may contact a detection surface of the sensor when the intermediate transfer belt is replaced with a new one, causing damage to the sensor. JP-2001-34032-A discloses a technique to dispose the sensor to be separable from the intermediate transfer belt.
When the sensor is disposed separable from the intermediate transfer belt, a positioning device needs to be provided for precise positioning of the sensor. However, due to accumulated dimensional tolerances of each part and parts assembly errors, the sensor is not positioned with consistently high precision, thereby degrading sensor detection precision.
Therefore, the present invention aims to provide an optimal positioning device capable of properly positioning the sensor relative to the intermediate transfer belt.